function isLetter (c)
{ 
	return ( ((c >= "a") && (c <= "z")) || ((c >= "A") && (c <= "Z"))  )
}
 
 function isSpecialLetter (c)
 {
   return ( (c == ",") || (c == ".") || (c == " ") || (c == "&") || (c == "-") )
 }

function isDigit (c)
{ 
	return ((c >= "0") && (c <= "9"))
}


function isCharacters(s)
{
   
    for (var i = 0; i < s.length; i++)
    {   
	// Check that current character is number.
	var c = s.charAt(i);

	if (!( (isLetter(c)) || (isDigit(c)) || isSpecialLetter(c) )) 
	return false;
    }
    
    return true;
}


function isNumericals(s)
{
   
    for (var i = 0; i < s.length; i++)
    {   
	// Check that current character is number.
	var c = s.charAt(i);

	if (!( (isDigit(c)) || (c == "-" ) )) 
	return false;
    }
    
    return true;
}    